National Instruments VXI-MIO Series - Manual (Page 64)

Chapter 4 Signal Connections
VXI-MIO Series User Manual 4-18  National Instruments Corporation
Single-Ended Connection Considerations
A single-ended connection is one in which the VXI-MIO Series module
analog input signal is referenced to a ground that can be shared with
other input signals. The input signal is tied to the PGIA positive input,
and the ground is tied to the PGIA negative input.
When you configure every channel for single-ended input, up to 64
analog input channels are available.
You can use single-ended input connections for any channel signal that
meets all of the following conditions:
• The input signal is high level (greater than 1 V).
• The leads connecting the signal to the VXI-MIO Series module are
less than 10 ft (3 m).
• The input signal can share a common reference point with other
signals.
DIFF input connections are recommended for greater signal integrity
for any input signal that does not meet the preceding conditions.
You can software-configure the VXI-MIO Series module channels for
two different types of single-ended connections—RSE configuration
and NRSE configuration. The RSE configuration is used for floating
signal sources; in this case, the VXI-MIO Series module provides the
reference ground point for the external signal. The NRSE input
configuration is used for ground-referenced signal sources; in this case,
the external signal supplies its own reference ground point and the
VXI-MIO Series module should not supply one.
In single-ended configurations, more electrostatic and magnetic noise
couples into the signal connections than in differential configurations.
The coupling is the result of differences in the signal path. Magnetic
coupling is proportional to the area between the two signal conductors.
Electrical coupling is a function of how much the electric field differs
between the two conductors.